This invention relates to a process for preparing linearly-extended polyalkylenepolyamines, such as diethylenetriamine and linear and branched triethylenetetramines. Linearly-extended polyalkylenepolyamines also include for the purpose of this invention alcohol-extended piperazines, such as N-(2-hydroxyethyl)piperazine, and amine-extended piperazines, such as N-(2-aminoethyl)piperazine.
Linearly-extended polyalkylenepolyamines find utility as dispersants, surfactants, chelants, catalysts, curing agents, and extenders in polyurethanes. In addition, linearly-extended polyalkylenepolyamines are useful starting materials or intermediates in the preparation of pesticides, veterinary antihelminthic pharmaceuticals, and high temperature lubricating oils.
It is known that non-cyclic polyalkylenepolyamines can be prepared by the reaction of an alkyl halide with ammonia or an amine. The product is a polyalkylenepolyamine hydrohalide salt, which must be neutralized with base in order to recover the valuable polyalkylenepolyamine product. The neutralization produces a waste stream of metal salt, which must be removed. Moreover, the process produces considerable amounts of undesirable cyclic compounds.
It is known that salt-free linear polyethylenepolyamines can be prepared directly by reacting an ethanolamine with an ethyleneamine in the presence of hydrogen and a hydrogenation catalyst. For example, U.S. Pat. No. 3,714,259 discloses such a process with preferred catalysts derived from the oxides of chromium, copper, nickel, and cobalt This process produces substantial quantities of undesirable cyclic products, such as piperazine. Moreover, this type of catalyst requires a large quantity of hydrogen to maintain the catalytic activity.
It is also known that alcohols can be directly animated in a less reductive environment. For example, U.S. Pat. No. 4,524,143 and U.S. Pat. No. 4,555,582 teach the preparation of predominantly linear polyethylenepolyamines comprising reacting ethylenediamine with monoethanolamine in the presence of a catalyst of zirconium silicate having phosphorus deposited thereon. Disadvantageously, this catalyst contains phosphorus compounds which can leach into the reaction mixture, react with amines, and plug the reactor.
European Patent Application 0 256 516 teaches the preparation of non-cyclic polyalkylenepolyamines comprising reacting an alkylenediamine, such as ethylenediamine, with an alkanolamine, such as monoethanolamine, in the presence of a catalyst containing niobium, specifically niobium oxides, niobium halides, and niobium alkoxides Suitable reactants for this process also include piperazine, hydroxyalkylpiperazines and aminoalkylpiperazines.
U.S. Pat. No. 4,827,037 teaches a process of preparing polyalkylenepolyamines by reacting an alkyleneamine with an alkanolamine in the presence of a catalytically effective amount of a Group IIIB or IVB metal acid phosphate, such as lanthanum acid phosphate or zirconium phosphate, or a Group IVB sulfate or nitrate, such as zirconium sulfate or zirconium nitrate. The Group IIIB acid phosphates are taught to include the dihydrogen phosphates of scandium, cerium, samarium, europium, thulium, erbium, ytterbium, yttrium, lutetium, thorium, neodymium, praseodymium, dysprosium and gadolinium. U.S. Pat. No. 4,463,193, U.S. Pat. No. 4,578,517, and U.S. Pat. No. 4,617,418 teach along similar lines. Disadvantageously, some of these catalysts may disintegrate in the presence of water.
U.K. Patent Application 2,147,896A discloses a process of forming diethylenetriamine by reacting monoethanolamine with ammonia in the presence of ethylenediamine and a metal phosphate catalyst wherein the metal is chosen from Groups IIIB, IVB, VB and IIIA of the Periodic Table among others. Thus, lanthanum, yttrium, zirconium, titanium, vanadium, and niobium phosphate catalysts are disclosed. Disadvantageously, some of these catalysts may also disintegrate in the presence of water.
U.S. Pat. No. 4,540,822 discloses a process for preparing predominantly linear polyethylenepolyamines from ethylenediamine and monoethanolamine employing a catalyst comprising a phosphorus compound deposited on a Group IVB metal oxide, such as titanium, zirconium and hafnium oxides. U.S. Pat. No. 4,578,518, U.S. Pat. No. 4,578,519, U.S. Pat. No. 4,584,406 and U.S. Pat. No. 4,588,842 teach along similar lines. Disadvantageously, phosphorus may leach out of these catalysts causing catalyst deactivation and reactor plugging.
It would be advantageous to have a process which eliminates the need for neutralizing hydrohalide salts and disposing of a waste salt stream. It would be more advantageous to have a process for the direct animation of aliphatic alcohols to polyalkylenepolyamines which also does not require expensive metals and large quantities of hydrogen. It would be even more advantageous if such a process produces a high selectivity for linearly-extended products and low selectivity for undesirable cyclic materials. It would be most advantageous if the catalyst for such a process is insoluble in the presence of amines and retains its physical integrity in the presence of water. In such a process the problems of catalyst leaching, reactor plugging, and catalyst separation would be avoided. Accordingly, the combined aforementioned advantages would render the animation process suitable for industrial applications.